import { promises as fs } from "fs";

import { CryptContainer } from "./CryptContainer";
import * as crypto  from "crypto";
import * as path  from "path";
import * as bcrypt from "bcrypt";

import { CryptSettings } from "./CryptSettings";
import { Files } from "../files/Files";
import { RJLog } from "../log/RJLog";


export class CryptIO
{
  static readonly encryptionSuffix = ".crypt";
  static readonly debugOutput = true;
  static readonly debugOutputSuffix = ".crypt.json";

  private static _cryptSettings:CryptSettings; 
  
  static set cryptSettings( cryptSettings:CryptSettings )
  {
    this._cryptSettings = cryptSettings;
  }

  static createUUID()
  {
    return crypto.randomUUID();
  }

  static isDebugFilePath( filePath:string ):boolean
  {
    return filePath.endsWith( this.debugOutputSuffix );
  }
  
  static async hash( data:string ):Promise<string>
  { 	
    let hash = await bcrypt.hash( data, 10 );
    return Promise.resolve( hash );
  }

  static async verifyHash( data:string, hashed:string ):Promise<boolean>
  {
    let isVerified = await bcrypt.compare( data, hashed );
    return Promise.resolve( isVerified );
  }
  
  static async encrypt( data:string, settings?:CryptSettings ):Promise<string>
  {
    settings = settings || CryptIO._cryptSettings;

    const algorithm = 'aes-192-cbc';

    const key = crypto.scryptSync( settings.publicKey, 'salt', 24 );

    const cipher = crypto.createCipheriv( algorithm, key, settings.iv );

    let encrypted = cipher.update( data, 'utf8', 'hex');
    encrypted += cipher.final('hex');

    return Promise.resolve( encrypted );
  }

  static async decrypt( data:string, settings?:CryptSettings  )
  {
    settings = settings || CryptIO._cryptSettings;

    const algorithm = 'aes-192-cbc';

    const key = crypto.scryptSync( settings.publicKey, 'salt', 24 );
    
    const decipher = crypto.createDecipheriv( algorithm, key, settings.iv );
        
    let decrypted = decipher.update( data, 'hex', 'utf8' );

    decrypted += decipher.final('utf8');   
    
    return decrypted;
  } 

  static async createWithRandomUUID<T>( parentPath:string, data:any, onUUID?:( uuid:string, data:T ) => T ):Promise<string>
  {
    let uuid = CryptIO.createUUID();
    let fullPath = path.join( parentPath, uuid + this.encryptionSuffix );

    let pathExists = await Files.exists( fullPath );

    while ( pathExists )
    {
      uuid = CryptIO.createUUID();
      fullPath = path.join( parentPath, uuid + this.encryptionSuffix );
      pathExists = await Files.exists( fullPath );
    }
          
    if ( onUUID )
    {
      data = onUUID( uuid, data );
    }

    await CryptIO.saveJSON( fullPath, data );
    
    

    return Promise.resolve( uuid );
  }

  static async loadWithRandomUUID<T>( parentPath:string, uuid:string ):Promise<T>
  {
    let fullPath = path.join( parentPath, uuid + this.encryptionSuffix );

    let fileExsits = await Files.exists( fullPath );

    if ( ! fileExsits )
    {
      return Promise.resolve( null );
    }

    let data = await this.loadJSON<T>( fullPath );

    return data;
  }

  static async deleteWithRandomUUID( parentPath:string, uuid:string ):Promise<boolean>
  {
    let fullPath = path.join( parentPath, uuid + this.encryptionSuffix );

    let exists = await Files.exists( fullPath );

    if ( ! exists )
    {
      return Promise.resolve( false );
    }

    await Files.deleteFile( fullPath );

    return Promise.resolve( true );
  }

  static async updateWithRandomUUID( parentPath:string, uuid:string, data:any ):Promise<void>
  {
    let fullPath = path.join( parentPath, uuid + this.encryptionSuffix );
    await this.saveJSON( fullPath, data );

    return Promise.resolve();
  }

  static async saveJSON( path:string, data:any ):Promise<void>
  {
    let jsonString = JSON.stringify( data );

    RJLog.log( "Saving ", data, ">>", jsonString,  );
    
    let container:CryptContainer = 
    {
      key:"",
      data: await this.encrypt( jsonString )
    };

    let containerString = await this.encrypt( JSON.stringify( container ) );
    
    await fs.writeFile( path, containerString );

    if ( this.debugOutput )
    {
      await fs.writeFile( path + this.debugOutputSuffix, jsonString );
    }

    return Promise.resolve();
  }
  
  static async saveUTF8( path:string, jsonString:string ):Promise<void>
  {
    RJLog.log( "Saving ", jsonString,  );
    
    let container:CryptContainer = 
    {
      key:"",
      data: await this.encrypt( jsonString )
    };

    let containerString = await this.encrypt( JSON.stringify( container ) );
    
    await fs.writeFile( path, containerString );

    if ( this.debugOutput )
    {
      await fs.writeFile( path + this.debugOutputSuffix, jsonString );
    }

    return Promise.resolve();
  }
  

  static async loadJSON<T>( path:string ):Promise<T>
  {
    let encryptedContainerString = await fs.readFile( path );
    let containerString = await this.decrypt( encryptedContainerString.toString() );    
    
    let container = JSON.parse( containerString ) as CryptContainer;
    let encryptedData = container.data;
    let jsonString = await this.decrypt( encryptedData );

    let json = JSON.parse( jsonString ) as T;

    return Promise.resolve( json );
  }

  static async loadUTF8( path:string ):Promise<string>
  {
    let encryptedContainerString = await fs.readFile( path );
    let containerString = await this.decrypt( encryptedContainerString.toString() );    
    
    let container = JSON.parse( containerString ) as CryptContainer;
    let encryptedData = container.data;
    let jsonString = await this.decrypt( encryptedData );

    return Promise.resolve( jsonString );
  }

  
}